30 Apr 2011
Devils Hole II is a tectonic opening into the regional, slightly thermal (33°C) aquifer underlying the Amargosa desert at the southern Nevada-California border. In the lower chamber of the cave, near the water table, the cave walls are coated with thick crust of phreatic calcite. It is known from pevious studies in the Devils Hole cave located nearby (e.g., Winograd et al., Science 1992) that this calcite provides a continuous ca. 500 000 year-long palaeoclimate record.
Having acquired sampling permit from the Death Valley National Park to which the cave belongs, Yuri Dublyansky and Christoph Spötl drilled the crust and collected cores. They also surveyed the cave and performed limited cave-climate observations.
Observations and preliminary analyses suggest that during most of the 500,000 year-long growth history the water table was substantially (up to 9 m) higher than it is today; only during three intervals it declined to near its present-day position. The cores will be used to reconstruct the isotopic composition of palaeogroundwater in this part of the Southern Great Basin via fluid-inclusion studies.